The present invention relates to forage harvesters having rotating cutting cylinders and an elongated cutter bar supported in closely adjacent relationship to the cutting cylinder whereby crop material can be chopped between knives supported by the cutting cylinder and the cutter bar. More particularly, the invention relates to means for adjustably supporting the cutter bar along its length such that every portion of the cutter bar can be accurately positioned relative to the knives of the cutting cylinder and in such a manner that the center portion of the cutter bar is not permitted to bend or otherwise deform under the cutting force of the knives.
The forage harvesters which have been more recently developed have increased crop handling capacities and have included cutting cylinders of increased length. As a result of the use of longer cutting cylinders, complementary cutter bars have also become elongated to the extent that the cutter bars may tend to deflect or otherwise distort at their mid-sections due to the force on the cutter bar generated by crop material being cut between the cutting cylinder and the cutter bar.
Some of the prior art apparatus have sought to prevent this distortion of the cutter bar by securing the center portion of the cutter bar to the cutter bar support structure by a bolt or the like. However, it is generally necessary to regrind or sharpen the blades of the cutting cylinder thereby changing the gap between the cutting edge of the blades and the cutter bar and consequently it is necessary to adjust the relative position of the cutter bar. The prior art means for supporting the center portion of the cutter bar make such adjustment difficult because they are difficult to reach, requiring the operator to crawl under the forage harvester first to loosen the bolt and then later to secure the bolt after adjusting the position of the cutter bar.